Is it Possible to Reuse the University of Pennsylvania Smell Identification Test (UPSIT^®)? The "2 Zs" Protocol

Introduction  The University of Pennsylvania Smell Identification Test (UPSIT^®) is a reliable olfactory test that is easy and quick to apply. It is a one-time use test and its reuse is not recommended by the manufacturer.

Objectives  Because in high-demand healthcare facilities testing all patients with UPSIT^® can be costly, in this present study we sought to assess the feasibility of reusing the UPSIT.

Methods  Two hundred and ninety healthy volunteers aged 18 and 40 without olfactory complaints participated in the study. Two hundred and forty volunteers underwent the UPSIT^® scratching the small strip of the test doing only 2 Z-shaped scratches ("2 Zs" protocol); each UPSIT^® was used 20 times by same-sex participants. The remaining fifty patients performed the UPSIT^® in the standard single-use fashion. Adjusted multiple regressions relating to the olfactory test score, number of times the test was applied, and demographic variables were performed.

Results  The mean scores using the UPSIT^® repeatedly were lower than those done in the single-use standard fashion. Despite this, the scores remained stable until the tenth time the test was applied. When patients perform the UPSIT^® in the "2 Zs" protocol, a correction factor of more 3 points was required in the final score.

Conclusion  UPSIT^® reuse up to 10 times is feasible when a 3-point correction factor is added to the final score. The "2 Zs" protocol described is an alternative to reduce costs in epidemiological studies. This study, however, is limited as it was carried out only with healthy individuals.

Keywords
smell; olfactory perception; olfaction disorders; anosmia; economics